This light is actually a 5 by 5 grid of lights spanning 0.3 units in the
x direction and 0.3 units in the y direction (although each light is
moved slightly by the JITTER keyword). This creates softer shadows.

See the example attached to the end of this file as a main-level program
(only available if you have the source code version of this routine):

IDL> .run mggrpovraylight__define

This should produce output with an area light (which makes a fuzzy
shadow):